Hybrid Mixed-Metal Oxide Latex Composite Thin Films for Passive Control of Indoor Formaldehyde

Abstract

This study presents the preparation, characterization, and formaldehyde (HCHO) adsorption performance of hybrid mixed-metal oxide (MMO)–coated latex composites for indoor air quality control. The hybrid MMO–latex composites were prepared by coating a thin layer of TiO2/SiO2 particles onto a latex polymer film using polypropylene glycol (PPG) to aid in uniform deposition of MMO particles via hydrogen bonding, while also providing additional active sites for HCHO adsorption. The effect of PPG content on the HCHO removal performance of the composites in terms of capture capacity and kinetics were systematically investigated. The indoor chamber tests indicated that the HCHO adsorption capacity and kinetics of the composite thin film increased by 36% and 63%, respectively, compared to those of its MMO-incorporated latex analogue under identical conditions. Moreover, our results indicated that upon increasing the PPG content from 0 to 90 wt %, the HCHO adsorption capacity and rate were significantly enhanced from 0.36 to 0.57 mmol/g and 0.01 to 0.14 h–1, respectively, due to increased affinity and better accessibility to the adsorption active sites in the thin films with uniformly deposited MMO particles. The increase in the humidity level from 45 to 80% RH was also found to promote the rate of HCHO capture by 50%. The findings of this work demonstrate that hybrid MMO–coated latex composites have superior HCHO adsorptive performance compared to their incorporated MMO–latex analogues.